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NASA
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System, Wilfrid Schroeder (Land Atmosphere Near Real-Time Capability for EOS Fire Information for Resource Management). 2016. “VIIRS Active Fire Locations 375m FIRMS V001 NRT.” NASA Land Atmosphere Near real-time Capability for EOS Fire Information for Resource Management System. https://doi.org/10.5067/firms/viirs/vnp14imgt.nrt.001.
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We acknowledge the use of data and imagery from LANCE FIRMS operated by the NASA/GSFC/Earth Science Data and Information System (ESDIS) with funding provided by NASA/HQ.
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2020
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Near Real Time
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Global
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375 m
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The data is collected from the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on Suomi-National Polar-Orbiting Partnership (Suomi-NPP) satellite.
Fire detections are determined using a multispectral contextual algorithm to identify subpixel fire activity and other thermal anomalies in the Level 1 (swath) input data. The algorithm uses all five 375 m VIIRS channels to detect fires and separate land, water, and cloud pixels in the image. Fire locations are then given as the center of a 375 m pixel that has been flagged by the algorithm.
The algorithm first screens for cloud and water pixels. Next potential fires are found using criteria based on brightness detected by the channels. These fires are then filtered by the algorithm to find the distinct radiometric signatures associated with active fires. Finally custom filters are applied to reduce false alarm rates. False alarms usually come from areas of high solar reflection such as metallic rooftops in industrial parks or bright surfaces such as concrete pavement.
Confidence values are available for each fire detection. They are based on a collection of intermediate algorithm quantities used in the detection process and are intended to help users gauge the quality of individual hotspot/fire pixels. Confidence values are set to low, nominal, and high. Low confidence daytime fire pixels are typically associated with areas of sun glint and lower relative temperature anomaly (<15K) in the mid-infrared channel I4. Nominal confidence pixels are those free of potential sun glint contamination during the day and marked by strong (>15K) temperature anomaly in either day or nighttime data. High confidence fire pixels are associated with day or nighttime saturated pixels.
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NASA considers current fire data to have good enough quality for fire management applications and scientific studies but cautions users to be aware of data quality limitations associated with archived data. The VIIRS active fire algorithm undergoes routine quality control to be refined. Not all fires are detected. There are several reasons why VIIRS may not have detected a certain fire. The fire may have started and ended between satellite overpasses. The fire may have been too small or too cool to be detected in the 375 m pixel. Cloud cover, heavy smoke, or tree canopy may completely obscure a fire. It is not recommended to use active fire locations to estimate burned area due to spatial and temporal sampling issues.
Each fire alert has a confidence value of low, nominal, or high to help users gauge the quality of detection.
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GOAL 13: Climate action, GOAL 15: Life on Land
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